Suction brush for vacuum cleaner

ABSTRACT

A suction brush for a vacuum cleaner has a bottom plate rotatably disposed under a cover to contact with a cleaning surface. Even when the rear end of the suction brush separates apart from the cleaning surface during the cleaning operation, the bottom plate maintains the close contact with the cleaning surface by rotating downward, thus enhancing the cleaning efficiency.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to copending U.S. applications entitled “Suction Brush Assembly Having Rotation Roller for Sweeping Dust,” Ser. No. 10/195,595, filed Jul. 16, 2002, and “Bendable Suction Brush for Vacuum Cleaner,” Ser. No. 10/851,080, filed May 24, 2004.

REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 2004-53312, filed on Jul. 9, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention concerns a vacuum cleaner. More particularly, the present invention concerns an improved suction brush that adjusts to different characteristics of a cleaning surface, such as a carpet or floor, so as to enhance cleaning efficiency and accuracy.

BACKGROUND OF THE INVENTION

A vacuum cleaner generally draws in dust and contaminants on a cleaning surface using a suction force generated by the driving of a vacuum source disposed in a body of the vacuum cleaner. Referring to FIG. 1, the vacuum cleaner includes a cleaner body 10, a suction brush 30, and an extension path 20. The cleaner body 10 accommodates a motor (not shown) generating the suction force, and the suction brush 30 is provided with an inlet 39 which faces the cleaning surface and through which dust is drawn. The dust drawn in through the suction brush 30 flows through the extension path 20 which leads to the cleaner body 10.

The suction brush 30 includes an upper housing 34 and a lower housing 38 coupled by a plurality of bolts 40. The inlet 39 is formed at the lower housing 38, through which the dust is drawn in from the cleaning surface. The extension path 20 includes a connector 26 rotatably fit into the suction brush 30, an extension pipe 24 that fits with the connector 26, and a suction hose 22 that fits in the extension pipe 24 at one end and connects with the cleaner body 10 at the other end.

As structured and configured as above, the vacuum cleaner draws in dust and contaminants from the cleaning surface, such as a carpet or floor, while a user of the vacuum cleaner moves the suction brush 30 back and forth. However, when the suction brush 30 is moved backward, the rear end of the suction brush 30 is often lifted or spaced from the cleaning surface. With the rear end of the suction brush 30 spaced from the cleaning surface, the bottom of the lower housing 38 cannot closely contact the cleaning surface, thus bringing about loss of the suction force and deterioration of the cleaning accuracy. Also, when using the vacuum cleaner, the bottom of the lower housing 38 often directly contacts the cleaning surface, such as a floor, and thus scratches the floor.

In addition, since a plurality of bolts 40 are required to couple the upper housing 34 and the lower housing 38, the manufacture costs are increased and productivity decreased due to the increased number of parts and required assembly.

SUMMARY OF THE INVENTION

To overcome the above disadvantages and problems of the conventional arrangement, there is provided an improved suction brush for a vacuum cleaner to enhance cleaning accuracy and cleaning efficiency by closely contacting a bottom plate with the cleaning surface during the cleaning operation.

Another aspect of the present invention provides an improved suction brush for a vacuum cleaner, which is capable of preventing a bottom plate from scratching the floor during the cleaning operation

Yet another aspect of the present invention provides a suction brush for a vacuum cleaner providing improved assembly without employing fastening members, such as bolts.

The foregoing objects are basically attained by a suction brush for a vacuum cleaner having a cover, and a bottom plate having a suction port through which dust is drawn in from a surface being cleaned by a suction force generated by a vacuum source disposed in a body of the vacuum cleaner. The bottom plate is rotatably disposed at the cover.

The suction brush further comprises an elastic member disposed between the bottom plate and the cover so as to elastically bias an end of the bottom plate in a predetermined direction.

The suction brush further comprises a bottom plate stopper disposed on at least one of the bottom plate and the cover to limit the rotation of the bottom plate. Accordingly, the bottom plate rotates within a predetermined angle.

The suction brush further comprises a bottom plate fixing unit disposed between the cover and the bottom plate to selectively fix the bottom plate to the cover. The bottom plate fixing unit has a foot switch rotatably disposed in the cover, an operation knob exposed to the outside through an opening in the cover, a first locking part, a brush plate rotatably disposed in the cover to rotate in association with the foot switch, and a second locking part to lock and unlock the brush plate with the first locking part in a complementary manner.

Consistent with the above aspect of the present invention, the suction brush for the vacuum cleaner has a cover, a bottom plate rotatably disposed at the cover, and a bottom plate fixing unit disposed between the cover and the bottom plate. The bottom plate fixing unit has a foot switch rotatably disposed in the cover and a brush plate rotatably disposed in the cover to rotate in association with the foot switch. The foot switch has an operation knob exposed to the outside so that the user can rotate the foot switch. A first locking part is formed on both ends of the foot switch. A second locking part is formed at the brush plate in correspondence with the first locking part. When the second locking part rotates in association with the rotation of the first locking part, the brush disposed at a front part of the brush plate protrudes with respect to the cover. An elastic member is interposed between the front part of the brush plate and the bottom plate so as to press together the front part of the brush plate and the bottom plate.

The user can select a rotation mode and a stationary mode of the bottom plate through the operation knob. If the user selects the rotation mode, the front end of the bottom plate is biased downwardly by the elastic member and the rear end is supported by the bottom plate stopper. When a rear side of the suction brush separates apart from the cleaning surface, the bottom plate rotates and closely contacts the cleaning surface due to the suction force between the cleaning surface and the bottom plate and the force applied on the suction brush by the user.

When the user selects the stationary mode and rotates the foot switch by using the operation knob, the first locking part presses downward onto the second locking part so as to rotate the brush plate downwardly. The brush at the front end of the brush plate protrudes downwardly from the bottom plate. Since the suction brush is supported by a wheel at the rear end and the brush, the cleaning is performed with a predetermined gap from the cleaning surface. Accordingly, the cleaning surface, such as a floor, is not scratched. In addition, as the brush plate rotates downward, the elastic member presses the front end of the bottom plate downwardly. Thus, the front end of the bottom plate is supported by the elastic member, and the bottom plate stopper at the rear end of the bottom plate is supported by the end of brush plate support ribs formed at the cover so that the bottom plate is fixed with respect to the cover.

The foot switch, the brush plate, and the bottom plate, respectively, have a rotary axis. The cover is provided with support ribs having an axis hole corresponding to the rotary axis. The rotary axis and the support ribs are sloped so that the rotary axis is smoothly inserted into the axis hole. As constructed above, the assembly of the suction brush is improved and the number of the parts is reduced without having to use additional fastening means, such as bolts.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawing figures of which:

FIG. 1 is a perspective view of a conventional vacuum cleaner,

FIG. 2 is a perspective view of a suction brush of a vacuum cleaner according to an embodiment of the present invention, showing the suction brush assembled;

FIG. 3 is an exploded view of the suction brush of the vacuum cleaner illustrated in FIG. 2;

FIGS. 4A and 4B are partial elevational views, respectively, of the suction brush taken in section along the lines 4A-4A and 4B-4B of FIG. 3;

FIG. 5 is a perspective view of the bottom plate of the suction brush illustrated in FIG. 3;

FIG. 6 is an elevational view of the suction brush taken in section along the line VI-VI of FIG. 3;

FIG. 7 is an elevational view of the suction brush taken in section along the line VII-VII of FIG. 3;

FIGS. 8A and 8B are side elevational views of the suction brush of the vacuum cleaner with a portion of the suction brush removed according to an embodiment of the present invention; and

FIGS. 9A and 9B are side elevational views of the suction brush of the vacuum cleaner with a portion of the suction brush removed according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the drawings.

Referring to FIGS. 2 and 3, a suction brush for a vacuum cleaner according an exemplary embodiment of the present invention includes a cover 100 forming a upper casing, a bottom plate 150 rotatably fixed under the cover 100, a bottom plate fixing unit 300, a wheel 418, and a wheel shaft 420. The bottom plate fixing unit 300 is rotatably disposed between the cover 100 and the bottom plate 150. The unit 300 allows selection between rotating or fixating of the bottom plate 150 depending on the type of a cleaning surface, such as a carpet or a floor. The wheel 418 and the wheel shaft 420 are rotatably fixed to a rear end 102 of the cover 100.

The cover 100 is provided with a first bottom plate rotary axis 152 for fixing the bottom plate 150 at the inner sidewalls of the cover 100. Two second bottom plate support ribs 157 are provided with a second bottom plate axis hole 158 corresponding to a second bottom plate rotary axis 156 (FIG. 5). The second bottom plate rotary axes 156 are positioned coaxially with respect to the first bottom plate rotary axis 152. A suction duct 108 is formed between the second bottom plate support ribs 157, and is in fluid communication with an extension pipe connector 500. An opening 104 is formed at an upper side of the cover 100 for receiving an operation knob 314. Four brush plate support ribs 384 are formed in the cover 100 for rotatably fixing a brush plate 350. Each brush plate support rib 384 is provided with a brush plate axis hole 380 (FIG. 4B). Two foot switch support ribs 336 are formed in the front of the brush plate support rib 384 for rotatably fixing a foot switch 310 to the cover 100. Each foot switch support rib 336 is provided with a foot switch axis hole 334 into which a foot switch rotary axis 330 is inserted, which will be described below. At the rear end of the cover 100, a wheel receiving part 400 is formed for receiving the extension pipe connector 500 and the wheel 418. The wheel receiving part 400 is provided with a wheel shaft hole 410 for a lateral insertion of the wheel shaft 420. An axis hole (not shown) is formed at a front end of the extension pipe connector 500 corresponding to the wheel shaft hole 410. The wheel shaft 420 penetrates through the axis hole and the wheel shaft hole 410 so that the extension pipe connector 500 and the wheel 418 are rotatably fixed at the cover 100.

Both sidewalls of the bottom plate 150 are provided with a first bottom plate axis hole 154 corresponding to the first bottom rotary axis 152. The first bottom plate axis hole 154 fits with the first bottom rotary axis 152 formed at the inner sidewall of the cover 100 so as to enable the bottom plate 150 to rotate with respect to the cover 100. Accordingly, even when a rear side under the suction brush separates apart from the cleaning surface, the bottom plate 150 rotates with respect to the cover 100 in close contact with the clearing surface. At the bottom of the bottom plate 150 is formed a dust transfer channel 172 leading to a suction port 176. A spacer 174 is disposed in front and in rear of the suction port 176 for keeping a space between the bottom plate 150 and the cleaning surface. A rubber lip mount part 160 (FIG. 5) is formed at the rear end under the bottom plate 150 on which a rubber lip 168 is mounted for sweeping dust and contaminants not drawn in to the suction port 176 but passing to the rear end.

The bottom plate fixing unit 300 includes the foot switch 310 rotatably fixed at the cover 100 and the brush plate 350 mounted in the cover 100 and under the foot switch 310 for rotating in association with the foot switch 310.

The foot switch 310 is provided with the operation knob 314 at one end. The operation knob 314 is exposed through the opening 104 formed on the cover 100 so that the user of the vacuum cleaner can control the foot switch 310 from the outside. A first foot switch stopper 324 is formed at a rear end of the operation knob 314 for limiting excessive rotation of the foot switch 310. A first locking part 318 is formed at the other end of the foot switch 310 and extends downwardly from the operation knob 314. The first locking part 318 is a rib extending downwardly from under the operation knob 314 at the other end of the foot switch 310. Each end of the foot switch 310 is provided with a foot switch rotary axis 330. The foot switch rotary axis 330 is inserted into the foot switch axis hole 334 of the cover 100 so that the foot switch 310 is rotatably fixed at the cover 100. The foot switch rotary axis 330 has a slope S facilitating smooth insertion into the foot switch axis hole 334. A second foot switch stopper 328 is formed at a center of the foot switch 310 to link both ends of the foot switch 310 and to restrain the foot switch 310 from rotating in the other direction. The second foot switch stopper 328 restrains the foot switch 310 from rotating in the other direction over a predetermined angle by contacting the suction duct 108 formed at the cover 100.

Two brush plate rotary axes 376 are formed at the rear end of the brush plate 350. The brush plate rotary axes 376 are inserted into the brush plate axis hole 380 (FIG. 4B) formed at the cover 100 so that the brush plate 350 is rotatably fixed at the cover 100. A pair of second locking parts 358 are formed at the front of the brush plate rotary axes 376 and contact the first locking part 318. An elastic member receiving part 210 is formed at the center of the front part of the brush plate 350 for receiving an elastic member 200. The elastic member 200 is preferably a coil spring, but may be various elastic members with respective elasticities. The elastic member 200 is securely inserted into the elastic member receiving part 210 at one end, and is fixed at the front end of the bottom plate 150 at the other end so as to bias the bottom plate 150 in direction A. The front end of the brush plate 350 is provided with a brush mount part 368 for the mount of a brush 372. The brush 372 is mounted at the front end of the brush plate 350 and vertically moves with respect to the cover 100 depending on the rotation of the brush plate 350. The brush plate 350 rotates when the first locking part 318 presses and rotates the second locking part 358.

Referring to FIG. 3, assembly of the suction brush is described according to an exemplary embodiment of the present invention. The foot switch 310 is fixed at the cover 100. The operation knob 314 of the foot switch 310 is inserted into the opening 104, and the foot switch rotary axis 330 is pressed and inserted into the foot switch axis hole 334 of the cover 100. Then, the brush plate 350 is fixed at the cover 100. The brush plate rotary axes 376 are pressed and inserted into the brush plate axis hole 380 (FIG. 4B) of the cover 100. The pair of the second locking part 358 of the brush plate 350 contacts the first locking part 318 of the foot switch 310 with the brush plate 350 being fixed. The elastic member 200 is inserted into the elastic member receiving part 210 of the brush plate 350. Finally, the bottom plate 150 is fixed at the cover 100. The fixation of the bottom plate 150 is accomplished by pressing and inserting the first bottom plate axis hole 154 and the second bottom plate rotary axes 156 into the first bottom rotary axis 152 and the second bottom plate axis hole 158, respectively. The elastic member 200 is pressed and contacts the front end of the bottom plate 150 with one end. Hence, the elastic member 200 biases the front end of the bottom plate 150 to rotate in the other direction B and the rear end of the bottom plate 150 is biased by a bottom plate stopper 164 (FIG. 5). As structured and assembled, the bottom plate 150 maintains a level position with the cleaning surface.

Referring to FIGS. 4A and 4B, the brush plate support ribs 384, the foot switch support ribs 336, the first bottom rotary axis 152, and the second bottom plate support ribs 157 each have a slope S. The slope S facilitates the smooth insertion of the rotary axes 152, 156, 330, and 376 into the corresponding axis holes 154, 158, 334, and 380 while the bottom plate fixing unit 300 (FIG. 3) is fixed at the cover 100.

Referring to FIG. 5, the two second bottom plate rotary axes 156 correspond to the first bottom plate axis holes 154 on the same axis. The suction port 176 is formed between the second bottom plate rotary axes 156 by penetrating through the suction brush, through which dust is drawn in. The suction port 176 fluidly communicates with the suction duct 108 (FIG. 3). The rear end of the bottom plate 150 is provided with the rubber lip mount part 160 protruding upward. Both ends of the rubber lip mount part 160 are provided with the bottom plate stopper 164 restraining the bottom plate 150 from rotating in the other direction B over a predetermined angle. Preferably, the rubber lip mount part 160 serves as the bottom plate stopper 164, but it is possible to apply variations to such structure and configuration using a separate member as long as the function of the bottom plate stopper 164 is fulfilled. If the bottom plate 150 rotates to the other direction B over the predetermined angle, the bottom plate stopper 164 contacts the terminal end of the brush plate support ribs 384 formed at the rear end 102 of the cover 100 (FIG. 3), and thus the bottom plate 150 is strained from rotating further to the other direction B.

FIG. 6 illustrates the foot switch 310 in association with the brush plate 350. Referring to FIG. 6, the first locking part 318 rotates within a predetermined range by the operation knob 314 and between first and second positions P1 and P2. The first position P1 refers to a position of the first locking part 318 when the foot switch 310 is restrained from further rotation in one direction C. The foot switch 310 is restricted from rotating further in one direction C because the second foot switch stopper 328 (FIG. 3) contacts the suction duct 108. The second position P2 refers to a position of the first locking part 318 when the foot switch 310 is restrained from further rotation in the other direction D. The foot switch 310 is restrained from rotating further to the other direction D because the first foot switch stopper 324 contacts the cover 100. The second locking part 358 includes a first contact part 360 contacting the first locking part 318 when the first locking part is at the first position P1, and a second contact part 362 contacting the first locking part 318 when the first locking part 318 is at the second position P2. The second contact part 362 is above the first contact part 360 so that the end of the first locking part 318, which is in contact with the first contact part 360, contacts the second contact part 362 when the first locking part 318 moves from the first position P1 to the second position P2. The first locking part 318 presses downward onto the second locking part 358 so that the brush plate 350 rotates downwardly around the brush plate rotary axes 376.

FIG. 7 illustrates the wheel shaft 420 fixed at the cover 100. Referring to FIG. 7, one side of the wheel shaft 420 is provided with a locking projection 424 on the outer circumstance of the wheel shaft 420. A locking recess 414 is formed at an inner side of the wheel shaft hole 410 of the rear end of the cover 100 in correspondence with the locking projection 424. As shaped and configured above, the extension pipe connector 500 is inserted into the rear end of the cover 100 and the wheel 418 is fixed in the wheel receiving part 400. Then, the wheel shaft 420 is inserted into the wheel shaft hole 410 formed at the cover 100 and the extension pipe connector 500 (FIG. 3), thus rotatably fixing the extension pipe connector 500 and the wheels 418 at the cover 100. The locking projection 424 of the wheel shaft 420 is coupled to the locking recess 414 of the wheel shaft hole 410 of the cover 100. With this simple locking structure, the wheel 418 and the extension pipe connector 500 are rotatably connected to the suction brush. Thus, the assembly of the suction brush is improved and the number of the parts is reduced.

As seen in FIGS. 8A and 8B, the bottom plate 150 rotates in the rotation mode or is fixed in the stationary mode with respect to the cover 100. While cleaning on the cleaning surface, such as a carpet, a user operates the vacuum cleaner in the rotation mode because the bottom plate 150 is not in close contact with the cleaning surface since the rear end of the suction brush is spaced from the cleaning surface. Accordingly, the user selects the rotation mode to obtain the close contact of the bottom plate 150 with the cleaning surface. The bottom plate 150 rotates with respect to the cover 100 in the rotation mode even if the rear end of the suction brush is spaced from the cleaning surface. In contrast, the cleaning surface, such as a floor, may be scratched due to direct contact with the bottom plate 150. In order to maintain a proper gap between the bottom plate 150 and the cleaning surface to avoid scratching, the user operates the vacuum cleaner in the stationary mode with the brush 372 extending downwardly from the front end of the suction brush and with the front end of the suction brush being against the cleaning surface and the rear end of the suction brush being supported by the wheel 418.

FIG. 8A illustrates the rotation mode of the bottom plate 150 with respect to the cover 100, and the FIG. 8B illustrates the stationary mode. Referring to FIG. 8A, the second foot switch stopper 328 (FIG. 3) is biased by the suction duct 108 (FIG. 3) and restrained from rotating to the other direction C (FIG. 6). The first locking part 318 at the both ends of the foot switch 310 contacts the first contact part 360 of the second locking part 358 formed at the both sides of the brush plate 350. The front end of the bottom plate 150 is biased downwardly by the elastic member 200 and the rear end is supported because contact of the bottom plate stopper 164 with the terminal end of the brush plate support ribs 384. The front end of the brush plate 350 is biased upwardly by the elastic member 200 and the rear end is supported since the first contact part 360 of the second locking part 358 is supported by the first locking part 318.

When operating the vacuum cleaner in the rotation mode over the cleaning surface such as a floor, the user presses the rear end of the operation knob 314 and changes to the stationary mode. Still referring to FIGS. 8A and 8B, the first locking part 318 formed at the one end of the foot switch 310 and under the operation knob 314 rotates downward around the foot switch rotary axis 330. The first locking part 318 presses the second locking part 358 while moving from the first contact part 360 of the second locking part 358 to the second contact part 362. Thus, the brush plate 350 rotates downward around the brush plate rotary axes 376 so that the brush 372 moves and protrudes downward from under the bottom plate 150. The elastic member 200, which is disposed at the front end of the brush plate 350 and biases the brush plate 350 upwardly, is compressed due to the moment transferred from the first locking part 318. With the elastic member 200 compressed, the front end of the bottom plate 150 receives a larger recovery force facing downward at the rotation mode. Accordingly, the bottom plate 150 becomes stationary since the front end is biased by the compressed elastic member 200 with greater recovery force than the rotation mode, and the rear end is fixed since the bottom plate stopper 164 is supported by the terminal end of the brush plate support ribs 384. As a result, scratching of the floor is prevented in the stationary mode by the bottom plate 150.

FIGS. 9A and 9B are views of the bottom plate 150 rotating in the rotation mode. FIG. 9A illustrates that the rear end of the suction brush in complete contact with the cleaning surface. The bottom plate 150 is biased downward by the elastic member 200 at the front end, and is supported at the rear end by the bottom plate stopper 164 contacting the terminal end of the brush plate support ribs 384. Thus, the bottom plate 150 is level with the cleaning surface.

FIG. 9B illustrates that the rear end of the suction brush is spaced from the cleaning surface due to the rotation of the suction brush to a certain angle θ. The force applied on the suction brush by the user is transferred to the elastic member 200 via the cover 100, the foot switch 310, and the brush plate 350. Such a force is applied in a direction of compressing the elastic member 200 downwardly. A force of the bottom plate 150 adhering to the cleaning surface by the suction force results in a moment in a clockwise direction around the rotary axes 152 and 156. Such a moment compresses upward the elastic member 200 biased against the front end of the bottom plate 150. Therefore, the force of the bottom plate 150 compressing the elastic member 200 upward is greater than the force of compressing the elastic member 200 downward so that the bottom plate 150 rotates in the clockwise direction and remains level with the cleaning surface. Even when the rear end of the suction brush separates from the cleaning surface due to the difference between the force direction caused by the user on the suction brush and the movement direction of the suction brush, the bottom plate 150 can maintain close contact with the cleaning surface, thus enhancing the cleaning efficiency.

When the rear end of the suction brush returns to its original position after being separated from the cleaning surface, the bottom plate 150 rotates in a counterclockwise direction by the elastic member 200 compressing downward on the front end of the bottom plate 150. The bottom plate 150 rotates until the bottom plate stopper 164 contacts the terminal end of the brush plate support ribs 384, to thus return to its original position, as shown in FIG. 9A.

In light of the forgoing, even if the rear end of the suction brush is apart from the cleaning surface, the close contact with the cleaning surface is maintained, thus enhancing the cleaning efficiency. When cleaning over the cleaning surface, such as the floor, the user changes to the stationary mode. Then, a proper gap is maintained between the cleaning surface and the bottom plate 150, to avoid scratching the cleaning surface. This is because the brush 372 moves and protrudes downward from the bottom plate 150 and supports the front end of the suction brush, and the rear end is supported by the wheel 418.

Accordingly, the assembly of the parts of the suction brush improves without requiring a fastening means such as bolts because each rotary axis and each axis hole is provided with the corresponding slopes. In addition, the absence of the fastening means reduces the number of required parts.

While the exemplary embodiments of the present invention have been described, additional variations and modifications of the embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims shall be construed to include both the above embodiments and all such variations and modifications that fall within the spirit and scope of the invention. 

1. A suction brush for a vacuum cleaner, comprising: a cover, and a bottom plate rotatably connected to the cover, the bottom plate having a suction port through which dust is drawn in from a surface being cleaned, the dust being drawn in by a suction force generated by a vacuum source disposed in a body of the vacuum cleaner.
 2. The suction brush of claim 1, further comprising an elastic member disposed between the bottom plate and the cover so as to elastically bias an end of the bottom plate in a predetermined direction.
 3. The suction brush of claim 2, further comprising a bottom plate stopper disposed on at least one of the bottom plate and the cover to limit a rotation of the bottom plate.
 4. The suction brush of claim 3, further comprising a bottom plate fixing unit disposed between the cover and the bottom plate to selectively fix the bottom plate to the cover.
 5. The suction brush of claim 4, wherein the bottom plate fixing unit comprises: a foot switch rotatably disposed in the cover and having an operation knob extending through an opening of the cover and a first locking part; and a brush plate rotatably disposed in the cover to rotate in association with the foot switch and having a second locking part to lock and unlock the brush plate with the first locking part in a complementary manner.
 6. The suction brush of claim 5, further comprising a brush disposed at the brush plate that protrudes between the cover and the bottom plate according to the rotation of the brush plate.
 7. The suction brush of claim 4, further comprising foot switch support ribs formed on the cover at a certain interval and having an axis hole connectable with a foot switch rotary axis of the foot switch, wherein at least one of the foot switch rotary axis and the brush plate support ribs is provided with a slope so that the foot switch rotary axis is pressed and inserted into the axis hole.
 8. The suction brush of claim 4, further comprising brush plate support ribs formed at the cover at a certain interval and having an axis hole connectable with a brush plate rotary axis of the brush plate, wherein at least one of the brush plate rotary axis and the brush plate support ribs is provided with a slope so that the brush plate rotary axis is pressed and inserted into the axis hole.
 9. The suction brush of claim 1, further comprising: a bottom plate rotary axis formed on at least one of the bottom plate and the cover, and bottom plate support ribs having an axis hole connectable with the bottom plate rotary axis, and the bottom plate support ribs formed on at least one of the cover and the bottom plate corresponding to the bottom plate rotary axis, wherein at least one of the bottom plate rotary axis and the bottom plate support ribs is provided with a slope so that the bottom plate rotary axis is pressed and inserted into the axis hole.
 10. The suction brush of claim 1, further comprising: a wheel and a wheel shaft; a wheel receiving part formed at a rear of the cover for receiving the wheel and having a shaft hole through which the wheel shaft is inserted; a locking projection formed on the wheel shaft; and a locking recess formed at the shaft hole corresponding to the locking projection so that the wheel shaft is inserted into and locked with the shaft hole.
 11. A suction brush for a vacuum cleaner comprising: a cover, a bottom plate rotatably connected to the cover, the bottom plate having a suction port through which dust is drawn in from a surface being cleaned, the dust being drawn in by a suction force generated by a vacuum source disposed in a body of the vacuum cleaner, a foot switch rotatably disposed in the cover and having an operation knob extending through an opening of the cover and a first locking part; a brush plate rotatably disposed in the cover to rotate in association with the foot switch and having a second locking part to lock and unlock the brush plate with the first locking part in a complementary manner, and a brush disposed at the brush plate protruding between the cover and the bottom plate according to the rotation of the brush plate. 